I own civic ek sedan with D16Y4 engine with auto transmission. I have installed performance headers 4-2-1 after installation I faced an issue during low rpm (during heavy traffic), engine started to vibrate and then lose power and throttle response gets dead if I push throttle to half way it makes engine stop and during high rpm it's performance is awesome. While in neutral car remains normal. Headers details, Diameter of 4 pipes is 1.75" while 2 pipes diameter is 2" and reset of measurement is same as 2" pipe. O2 sensor is installed at end of headers pipe.

How I overcome this issue? Thanks in advance

  • 1
    Are you sure it is the headers? Have you tested under other low-rpm conditions? Have you re-fitted the original headers and tested for the condition? PS saying it was fine before, won't preclude the possibility of a developing issue... Have you read for any error codes?
    – Solar Mike
    Commented Jan 23, 2019 at 7:06
  • Yeah I'm sure it's headers issue. I have removed headers and issue is gone. No I haven't got any engine check light with performance headers.
    – Shoaib
    Commented Jan 23, 2019 at 7:11
  • How do they compare to the original? how are the joints between the pipe sections? any steps or lumps can cause curious flow effects at particular rpm / flow rates... ie reverse flows etc
    – Solar Mike
    Commented Jan 23, 2019 at 7:15
  • The stock one is 4-1 not sure about diameter of 4 pipe stock exhaust manifold however 1 pipe is 2" diameter for stock one. Which is same as performance headers measurement. There was no leaks in performance headers.
    – Shoaib
    Commented Jan 23, 2019 at 7:18
  • I did not ask about leaks...
    – Solar Mike
    Commented Jan 23, 2019 at 7:51

1 Answer 1


When you install headers on ANYTHING, be it a Honda or a big block Camaro, you are making the engine flow more exaust gas than before. You need to compensate your air intake and fuel delivery to make up.for the loss in back pressure that the stock exaust created and the system as a package was designed with and built to meet emissions laws as such. Go to the header manufacturer and check with them to see if they have specific recommendations with the use of their products ( your particular system and application) example:. I put free flowing mufflers on my Harley and afterward it wouldn't idle. I had to put richer Jets in to make it run correctly. This is normal!

  • I was thinking for bigger injectors but wasn't sure that's why I didn't bought it. I am already using cold air intake with 3" pipe with stock throttle body. That means if I put bigger injectors then I'll have to sacrifice for fuel economy.
    – Shoaib
    Commented Jan 24, 2019 at 6:23
  • Thus the drawbacks of performance....you can't make a cake without using a bunch of ingredients. You may not experience less MPG, sometimes things get a little better but then after you reach a certain point it drops off like a thief... Commented Jan 24, 2019 at 6:46

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .